Failure analysis of torsional buckling of all-terrain crane telescopic boom section

A telescopic boom section (TBS) is a type of slender thin-walled structure equipped in all-terrain cranes. It has an irregular cross-section and bears complex multi-directional loads; thus, local buckling failure is apt to occur under large hoisting loads, sudden rotation brakes or gusts. In this study, the torsional buckling of a TBS under multi-directional loads is investigated. To accurately and quickly predict the buckling load of the TBS, geometric, material and status nonlinear finite element (FE) analyses with implicit and explicit methods were used to study the telescopic boom of an all-terrain crane QAYX. The critical buckling load obtained using the displacement, strain and stress were discussed, in which the load obtained using the stress state transition was closest to the experimental critical buckling load. The implicit method required less computational time and demonstrated a qualitatively good agreement with the strain measurements before reaching buckling failure. The explicit method calculated an accurate deformation when compared with the experimental result and implicit method; however, a large local deformation resulted in the calculation of the implicit method being unable to converge after buckling.